1. Field of the Invention
This invention relates to a capacitor-discharge ignition (CDI) system for an internal combustion engine, more particularly to the CDI system for an engine that can surely stop the engine at any time if needed.
2. Description of the Related Art
The CDI system for an internal combustion engine generally includes a power generation coil which is fixed on the engine body inside a rotating flywheel to generate electric power when crossing the fluxes of magnets fastened on the inner wall of the rotating flywheel, and a capacitor which stores the electric power produced by the power generation coil. When a switching element such as thyristor is turned on, the charge stored in the capacitor is discharged to the primary winding of an ignition coil through the switching element so as to produce high voltage for ignition in the secondary winding, as taught, for example, in Japanese Utility Model Publication No. Hei 6 (1994)-6229.
In the ignition system, an engine stop switch is installed to be manipulated by an operator. When the stop switch is turned on by the operator, the power generation coil or primary ignition coil is grounded or short-circuited such that the engine is stopped. However, if wire breakage occurs in the switch circuit, it becomes impossible to stop the engine.